As discussed in #19 and https://github.com/Homebrew/homebrew/issues/25249, there are some serious issues installing railsinstaller on 10.9 - it leaves the developer tools in an inconsistent state that may not be restorable without Time Machine or an OS reinstall. Given this, if there is no 10.9 version of the railsinstaller package, railsinstaller should refuse to install on 10.9 at all.
As discussed in #19 and https://github.com/Homebrew/homebrew/issues/25249, there are some serious issues installing railsinstaller on 10.9 - it leaves the developer tools in an inconsistent state that may not be restorable without Time Machine or an OS reinstall. Given this, if there is no 10.9 version of the railsinstaller package, railsinstaller should refuse to install on 10.9 at all.